[all-commits] [llvm/llvm-project] 4c6cba: [clang][NFC] Specify Type and ExtQuals as having 1...

[Vlad Serebrennikov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4c6cba31aaaa767cdb7f83ec4ca0eab9b6eae127
      https://github.com/llvm/llvm-project/commit/4c6cba31aaaa767cdb7f83ec4ca0eab9b6eae127
  Author: Vlad Serebrennikov <serebrennikov.vladislav at gmail.com>
  Date:   2023-10-12 (Thu, 12 Oct 2023)

  Changed paths:
    M clang/include/clang/AST/Type.h

  Log Message:
  -----------
  [clang][NFC] Specify Type and ExtQuals as having 16-byte alignment (#68377)

While working on LLDB visualizer for `QualType`, I stumbled upon `Type` and `ExtQuals` defined with `alignas(8)`. Such alignment leaves only 3 lower bits available for pointer tagging, whereas `QualType` requires 4 (3 qualifiers + discriminator between `Type *` and `ExtQuals *`). Turns out `Type` and its derived classes are allocated with `TypeAlignment == 16` passed to `Allocate()`. So I'm removing misleading `alignas(8)` and fixing corresponding static asserts. Since they are already allocated with 16-byte alignment, this is a non-functional change.